Fuelling your log burner

Section: Renewables

You’ve just installed your log burning stove and now you’re wondering where you can get the firewood you need to fuel it and just as importantly how much you will pay for the wood.

The choice is either to gather your own or source from suppliers. For most householders especially in urban areas, the first option is not terribly realistic which means turning to the market. As the popularity of stoves has grown, the supply of wood has increased to satisfy demand.

The merchants offering firewood vary from the professionals to the guy who is just advertising on the likes of Gumtree. While there can be bargains sourcing from someone who has found himself with a lot of wood he doesn't need, many will want to turn to an outfit which is reasonably well established.

Here again you have two options. You can buy kiln dried wood or wood that is advertised as seasoned. The former will have a moisture content under 20%. Seasoned wood will almost certainly have a moisture content over 20% but the exact figure will depend on how long it has been drying. If you want to check before you buy, invest in a moisture meter. You’ll need to split a sample log and test an interior surface.

Logs are sold in all sorts of bags but a typical container is a bulk bag with sides each measuring 0.9 metres, which has a volume of just over 0.7 cubic metres.

A bulk bag of kiln dried hardwood is available at a range of prices from £90 to £125 whereas the same quantity of seasoned hardwood can be bought for around £70 to £75. Some suppliers deliver for free while others charge. So that has to be taken into consideration when working out the eventual cost.

Buying logs loose offers the scope for considerable savings. A cubic metre of seasoned hardwood is available from one supplier for £75.That’s equivalent to £55 for a bulk bag volume.

Seasoned wood has less energy per kg than kiln dried wood but the difference is marginal enough. That’s not the issue. For some stoves, it is recommended that they are fuelled with wood that has been dried to below 20%.

If you have such a stove, there is a solution. You can buy seasoned wood, stack it in your garden or yard and cover with a clear polycarbonate sheet. With a reasonable summer, not always guaranteed, you should be able to get the moisture content of your seasoned wood down close to 20%.

There is alternative which I have been working on which should allow stove owners to dry seasoned wood to kiln dried levels. Two years ago I installed a solar kiln. I established that with the use of such a device it was possible to dry wood successfully even if the results were a bit mixed. Last year with the help of an Invest NI grant and the assistance of the South West College, we produced a second prototype which was much more efficient. The design is currently being refined with the involvement of Ulster University. By the end of the summer I hope to have a third prototype which should be able to dry wood below 20% even with our changeable weather.